In the process of dry etching, CVD, or the like in semiconductor manufacturing processes, processing is performed inside a high vacuum process chamber (hereinbelow, also referred to as a vacuum chamber). In the processing, in order to discharge gas existing inside the vacuum chamber to form a constant high vacuum degree, for example, a vacuum pump such as a turbo-molecular pump is used.
In the vacuum chamber, chlorine-based or fluorine-based process gas is used. The process gas may disadvantageously cause corrosion of components inside the turbo-molecular pump. In order to prevent such corrosion, the following countermeasures have been conventionally performed.
Patent Literature 1 (JP 01-095595 Y) describes the invention in which electroless nickel plating is applied to a section (a housing 2, a stator blade 3, rotor 5, a rotor blade 6, a fixed tube 8, and the like) with which gas inside a vacuum chamber makes contact. However, which area of the surface of each of the components is coated with the electroless nickel plating is not specifically described.
Patent Literature 2 (JP 2001-193686 A) describes that the surface of an internal base member is coated with a coating layer which includes a black nickel alloy or a black chromium alloy and fine particles dispersively contained in the alloy. However, components such as a rotor blade body, a stationary blade, the inner face of a main body cylindrical section, the inner face of a flange, a spacer, a protection net, and an exhaust port are merely listed as an example of the internal member, and which area of the surface of each of the components is coated with the coating layer is not specifically described.
In a turbo-molecular pump, a component requiring strength such as a case may be made of a stainless material such as SUS304. Further, a component requiring elasticity such as a ring spring may be made of a spring steel material (SUP material) . The stainless material and the spring steel material contain Fe or Cr. When these components are corroded by process gas, metal particles containing Fe or Cr may be released from the corroded area.